// 2025/11/17
// 不同路径2

class Solution {
public:
    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
        if(obstacleGrid[0][0] == 1)
            return 0;
        int m = obstacleGrid.size(), n = obstacleGrid[0].size();
        vector<vector<int>> dp(m, vector<int>(n, 0));
        dp[0][0] = 1;
        for(int i = 1; i < m; i++)
        {
            if(obstacleGrid[i][0] == 1)
                break;
            dp[i][0] = dp[i - 1][0];
        }
        for(int j = 1; j < n; j++)
        {
            if(obstacleGrid[0][j] == 1)
                break;
            dp[0][j] = dp[0][j - 1];
        }
        for(int i = 1; i < m; i++)
        {
            for(int j = 1; j < n; j++)
            {
                if(obstacleGrid[i][j] == 1)
                    continue;
                dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
            }
        }
        return dp[m - 1][n - 1];
    }
};